从记事本开始创建自己的 Gui 字体类

Question

I am creating a Notepad in java. I need help as we know there is a Font chooser option in notepad. I want to add that option in my notepad as well but FontChooser class is also not available.

Therefore i am creating my own class. For that i am using listItems which contains various listItems Like PLAIN,BOLD,ITALIC and then set this value to the textField like in notepad happens.

My question is there is setFont() method in java and i am using it like in this way

public void itemStateChanged(ItemEvent e)
{
    List temp=(List)e.getSource();
    if(temp==list1)
    {
        tft.setText(list1.getSelectedItem());
        tft6.setFont(new     Font(list1.getSelectedItem(),,Integer.parseInt(tft4.getText())));
    }
    else if(temp==list2)
    {
        tft2.setText(list2.getSelectedItem());
        if(tft2.getText().equalsIgnoreCase("BOLD"))
        {
            tft6.setFont(new     Font(list1.getSelectedItem(),Font.BOLD,Integer.parseInt(tft4.getText())));
        }
        else if(tft2.getText().equalsIgnoreCase("ITALIC"))
        {
            tft6.setFont(new     Font(list1.getSelectedItem(),Font.ITALIC,Integer.parseInt(tft4.getText())));           }
        else if(tft2.getText().equalsIgnoreCase("PLAIN"))
        {
            tft6.setFont(new Font(list1.getSelectedItem(),Font.PLAIN,Integer.parseInt(tft4.getText())));    
        }

    }
    else if(temp==list3)
    {

        tft4.setText(list3.getSelectedItem());
        tft6.setFont(new Font(list1.getSelectedItem(),Font.BOLD,Integer.parseInt(tft4.getText())));
    }
}

look at temp==list2

I will have to check again and again tft2.eqaulsIgnoreCase() what othere i can do in the setFont(list1.getSelectedItem(),list2.getSelectedItem(),list3.getSelectedItem()) i cant do list2.getSelectedItem() because of Font.BOLD\\PLAIN\\ITALIC

What can i doo???

Answer 1

Any time any of the option change I think you just want to create a new Font using all of the current options. Then you can just use the following constructor:

Font(String name, int style, int size);

The other option is if you have a base Font, then you can apply one attribute to the Font by using:

font.deriveFont(...); 

This will allow you to change one property at a time. Read the API for the proper parameters to use for the attribute you want to change.

Answer 2

I cannot say I fully understand the question, but the code snippet shown has aspects to it that seem tortuous. Especially asking for the style and font size as text fields (it also precludes using both bold & italic at the same time).

I'd recommend to use check boxes for bold / italic and a spinner for font size. Then determining the correct font can be done as simply as follows.

private Font getFont() {
    String name = fontFamilyBox.getSelectedItem().toString();
    int style = Font.PLAIN;
    if (boldCheckBox.isSelected()) {
        style += Font.BOLD;
    }
    if (italicCheckBox.isSelected()) {
        style += Font.ITALIC;
    }
    int size = fontSizeModel.getNumber().intValue();

    return new Font(name, style, size);
}

Here is a Minimal, Complete, and Verifiable example that shows how it might be used (please post code in this form in future).

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.EmptyBorder;

public class FontChooserPad {

    private JComponent ui = null;
    JComboBox<String> fontFamilyBox;
    JCheckBox boldCheckBox = new JCheckBox("Bold");
    JCheckBox italicCheckBox = new JCheckBox("Italic");
    SpinnerNumberModel fontSizeModel = new SpinnerNumberModel(20, 6, 120, 1);
    JTextArea editArea = new JTextArea(
            "The quick brown fox jumps over the lazy dog.", 4, 40);

    FontChooserPad() {
        initUI();
    }

    public final void initUI() {
        if (ui!=null) return;

        ui = new JPanel(new BorderLayout(4,4));
        ui.setBorder(new EmptyBorder(4,4,4,4));

        JPanel controls = new JPanel();
        ui.add(controls, BorderLayout.PAGE_START);

        String[] fontFamilies = GraphicsEnvironment.
                getLocalGraphicsEnvironment().getAvailableFontFamilyNames();
        fontFamilyBox = new JComboBox<>(fontFamilies);

        controls.add(new JLabel("Font"));
        controls.add(fontFamilyBox);
        controls.add(boldCheckBox);
        controls.add(italicCheckBox);
        JSpinner sizeSpinner = new JSpinner(fontSizeModel);
        controls.add(sizeSpinner);

        editArea.setWrapStyleWord(true);
        editArea.setLineWrap(true);
        ui.add(new JScrollPane(editArea));

        ActionListener fontActionListener = (ActionEvent e) -> {
            changeFont();
        };
        boldCheckBox.addActionListener(fontActionListener);
        italicCheckBox.addActionListener(fontActionListener);
        fontFamilyBox.addActionListener(fontActionListener);
        fontFamilyBox.setSelectedItem(Font.SERIF);

        ChangeListener fontChangeListener = (ChangeEvent e) -> {
            changeFont();
        };
        sizeSpinner.addChangeListener(fontChangeListener);

        changeFont();
    }

    private void changeFont() {
        editArea.setFont(getFont());
    }

    private Font getFont() {
        String name = fontFamilyBox.getSelectedItem().toString();
        int style = Font.PLAIN;
        if (boldCheckBox.isSelected()) {
            style += Font.BOLD;
        }
        if (italicCheckBox.isSelected()) {
            style += Font.ITALIC;
        }
        int size = fontSizeModel.getNumber().intValue();

        return new Font(name, style, size);
    }

    public JComponent getUI() {
        return ui;
    }

    public static void main(String[] args) {
        Runnable r = () -> {
            try {
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } catch (Exception useDefault) {
            }
            FontChooserPad o = new FontChooserPad();

            JFrame f = new JFrame(o.getClass().getSimpleName());
            f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
            f.setLocationByPlatform(true);

            f.setContentPane(o.getUI());
            f.pack();
            f.setMinimumSize(f.getSize());

            f.setVisible(true);
        };
        SwingUtilities.invokeLater(r);
    }
}